Wire rope lubricant

ABSTRACT

A wire rope lubricant having a base fluid as a majority component, and a wax or polymer as a minority component wherein at least one of the base fluid and the wax, or polymer, is biodegradable. A method of forming a wire rope having a plurality of wire strands, the method including the step of applying the wire rope lubricant between the wire strands.

The present invention relates to a wire rope lubricant being at leastpartly, optionally substantially, biodegradable, and a wire ropeincluding such a lubricant.

Wire ropes are well known for both onshore and offshore use, inparticular in maritime situations. They can be used in all types ofmarine vessels, including ships, large boats, drilling units etc, andwire ropes are often selected for their flexibility, strength,resistance to deformation, and bending.

Wire ropes are generally formed of a number of heavy duty wires firstforming strands, and then twisting of a number of the strands together,optionally around or over a core, to form a final wire rope.

Wire ropes are frequently subject to significant wear and tear, andoften some corrosion, especially in maritime situations. It is naturallydesired to maintain the highest properties for the wire rope, and toavoid or minimise any damage thereto. Thus, the use of wire ropelubricants to benefit the wire rope in use is well known in the art.

Some wire rope lubricants are used during the stranding and closureoperation of wire rope manufacture, particularly to achieve integrationwithin or around the strands prior to the subsequent twisting. Some wirerope lubricants are alternatively or additionally regularly applied towire ropes in use to provide or continue any anti-wear or anti-corrosionproperties.

Conventional wire rope lubricants comprise a mineral base oil andthickener system, with one or more additives, typically at least ananti-corrosion additive. However, increasing environmental legislationaround the world, such as the requirement to obtain a Vessel GeneralPermit to allow a vessel into the waters of the United States of America(based on permissible discharges incidental to the normal operation of avessel), make the use of conventional wire rope lubricants a challenge.

Thus, according to one aspect of the present invention, there is aprovided wire rope lubricant comprising a majority base fluid componentand a minority of a wax or polymer component, wherein at least one ofthe base fluid and the wax or polymer is biodegradable.

In this way, the wire rope lubricant can be defined as an‘Environmentally Acceptable Lubricant’ (EAL) as currently defined inAppendix A of the USA EPA 2013 Vessel General Permit (VGP) regulationused to define lubricants in the art. In meeting these regulations theproduct will be classed as biodegradable, minimally toxic and nonbio-accumulative.

The biodegradability of the base fluid, wax or polymer can be measuredusing the Organisation for Economic Cooperation and Development (OECD)standard methodology known in the art, in particular Test No. 306entitled “Biodegradability in sea water” (1992).

The present invention is not limited by the nature of the base fluid,which may comprise one or more different components or fluids, fallingwithin the above definitions. By way of example only, and withoutlimitation, examples of suitable base fluids that are biodegradableinclude one or more of the following group: vegetable oil, such as rapeseed oil, castor oil, soya oil and synthetic esters.

The base fluid is preferably an oil, and many base oils or possiblecomponents therefor are known in the art. A number of these are definedin the Lubricant Substance Classification list (or “LuSC”—list), whichalso sets out their biodegradability and aquatic toxicity. The LubricantSubstance Classification list is a list of substances and brands thathave been assessed on its biodegradation/bioaccumulation, aquatictoxicity, and renewability and exclusion lists of substances by acompetent body. The assessment is based on a maximum treat rate allowedin a lubricant. The list is published on the EU Ecolabel website.

Preferably, the base fluid is biodegradable oil having a kinematicviscosity in the range 450-2000 centistokes (cSt, also being cm²/s), at40° C.

Optionally, the base fluid has a high temperature stability and a lowacid value (<0.2 mg KOH/g). The Total Acid Number (TAN) of a base fluidcan be measured using the ASTM D974 test procedure.

Optionally, the base fluid has a viscosity in the range 450-1000 cSt-ata temperature of 40° C., preferably in the range 600-1000 cSt at 40° C.,and more preferably in the range 800-900 cSt at 40° C.

Optionally, the base fluid has a viscosity in the range 40-450 cSt at atemperature of 100° C., preferably in the range 40-200 cSt at 100° C.,and more preferably in the range 40-80 cSt at 100° C.

Optionally, the wax or polymer of the wax or polymer component of thewire rope lubricant is biodegradable.

In one embodiment of the present invention, both the majority base fluidcomponent and the minority wax or polymer component are bothbiodegradable.

Typically, the wax or polymer is a solid or a solid-like substance atambient temperature, or any raised ambient temperature such as 40° C.

Optionally, the wax or polymer has a melting point in the range 70-100°C.

Optionally, the viscosity of the base fluid and the viscosity of themelted wax or polymer is the same (within a small range), or wholly orsubstantially similar, such that the viscosity of the wire ropelubricant including these components is predictable, and the viscosityproperties of the components wholly or substantially act in a similarmanner during any heating and cooling. This is especially where the waxor polymer is a solid at ambient temperature, and a liquid during anyhot application.

Optionally, the base fluid and wax or polymer lubricant compositionmaintain a single ‘phase’ (i.e. not becoming ‘two-phase’) upon heating,especially above the melting point of the wax or polymer.

Optionally, the wax or polymer comprises 5-15 wt % of the lubricant.

The wax or polymer may be a naturally occurring or wax or polymer inparticular based on plant oil or plant material, or be a synthetic waxor polymer. Preferably, the wax or polymer is able to provide ahomogenous mixture with the base fluid, and avoids or has a de minimusof any dissolution or separation on cooling from a higher temperature toan in use or ambient temperature.

Optionally, the wax is one or more of the group comprising: carnaubawax, rice wax, candililla wax, animal waxes such as beeswax, mineralwaxes and synthetic waxes.

Preferably, the wax is carnauba wax.

Carnauba wax is a refined wax obtained from the fronds of the Braziliantropical palm tree Copenicia cerifera and has the CAS no. 8015-86-9, theISN No. 903. Carnauba wax has a majority component based on a number ofaliphatic esters, and some diesters, as well as containing free acids,free alcohols, hydrocarbons and some resins. It has a melting point inthe range 80-86° C. Carnauba wax has an ester value between 71-93.

A synthetic wax intended to have the same properties of Carnauba wax, orsimilar or substantially similar properties, is included within thescope of the present application, having in particular wholly orsubstantially the same viscosity and melting point range.

Optionally, carnauba wax is useable as the minority component in therange 5-15 wt %.

Alternatively, the wax or polymer is polyethylene wax, useable as theminority component from 2-3 wt %.

Optionally, the wax or polymer is a blend of one or more waxes and/orpolymers, which can be blended in order to adjust the consistency andmelting range of the final product.

Suitable anti-corrosive, anti-oxidant and anti-wear additives orcomponents are known in the art, and include a range of products soldunder the Additin (registered trade mark) brand from RheinChemieincluding RC4803 and RC8012, as well products sold under the Irganox andIrgalube brand from BASF, including L57 and 349. The products includedare from the LuSC list mentioned hereinbefore.

In the wire rope lubricant of the present invention, the base fluidcomponent may comprise at least 70, 75, 80, 85 wt % of the lubricant,preferably in the range 88-91 wt %.

In the wire rope lubricant of the present invention, the wax or polymercomponent may comprise up to 15%, optionally in the range 2-10 wt %.

In the wire rope lubricant of the present invention the remainder can bequantum satis (q.s.), i.e. sufficient to make up 100 wt %, typicallybeing an anti-corrosive additive up to 5 wt %, an anti-wear additive upto 5 wt % and an anti-oxidant additive up to 2-3 wt %, with an overallpercentage generally being up to 13 wt %, typically a maximum of 5-6 wt%.

Optionally, the wire rope lubricant of the present invention has theformula;

base fluid 88-91 wt % oil wax or polymer 8-10 wt % carnauba waxadditives q.s.

Wire rope lubricants can be used both onshore and offshore, and thepresent invention includes the lubricant being utilised in bothapplications. Wire rope lubricants are most commonly used on-boardvessels or other offshore and maritime situations or locations formaintenance of the wire ropes.

Wire rope lubricants for in-service use are expected to have a good orhigh penetration rate into the wire rope, and provide corrosionprotection and anti-wear properties. Optionally, wire rope lubricantshave or form some adhesive properties and some also form a film aroundthe wire rope.

Some wire rope lubricants are also delineated between ‘heavy bodiedlubricants’ best suited for applications where the wire rope is exposedto an extreme or an abusive environment, and light-bodied lubricantshaving a lighter consistency to achieve better penetration of thelubricant into the interior of the wire rope. The wire rope lubricantsof the present invention can be adapted for any suitable consistencybased on the viscosity of base lubricant and level of wax or polymerthickener.

Wire rope lubricants can be applied to an existing wire rope using anyone of a number of known techniques, including spraying, dipping,painting, pneumatic or swabbing. Application is possible via automaticlubrication pneumatic ‘units’ through which a wire rope can pass,(available from Viper, Masto and CoreLube).

Wire rope lubricants can also be used during manufacture of a wire rope,in particular by application to one or more of the strands of the wirerope by one or more of the above techniques, or by ‘hot application’,prior to twisting of the strands to form the final wire rope. Theapplied wire rope lubricant is intended to form a layer or barrier,preferably a film, optionally also as a final outer surface of the wirerope once formed, to help protect the wire rope from corrosion.

Thus, according to a second aspect of the present invention, there isprovided a method of forming a wire rope having a plurality of wirestrands, comprising the step of applying a wire rope lubricant asdefined herein between the wire strands, typically prior to twisting ofthe wire strands to form the wire rope.

Thus, according to another aspect of the present invention, there isprovided a wire rope having a plurality of wire strands and including awire rope lubricant as defined herein.

Typically, applied wire rope lubricant becomes depleted or contaminatedover a period of time, and one or more new or further applications ofthe wire rope lubricant can be made to a wire rope, typically whilst thewire rope remains in use or in situ.

According to a further aspect of the present invention, there isprovided the use of a wire rope lubricant as defined herein, wherein thelubricant is applied to a wire rope.

1. A wire rope lubricant comprising a majority base fluid component of avegetable oil and a minority of a wax or polymer component, wherein thewax or polymer component comprises 2-10 wt % of the lubricant, and atleast one of the base fluid and the wax or polymer is biodegradableaccording to the Appendix A of the USA EPA 2013 Vessel General Permit(VGP) regulation; and one or more additives of the group comprising:anticorrosive, anti-oxidant and anti-wear additives.
 2. The wire ropelubricant as claimed in claim 1 wherein the wax or polymer component isbiodegradable.
 3. The wire rope lubricant as claimed in claim 1 whereinthe wax is a plant based.
 4. The wire rope lubricant as claimed in claim1 wherein the wax is based on plant oil or plant material.
 5. The wirerope lubricant as claimed in claim 4 wherein wax is one or more of:carnauba wax, rice wax, candililla wax, animal waxes, mineral waxes orsynthetic waxes.
 6. The wire rope lubricant as claimed in claim 1wherein the wax is carnauba wax.
 7. The wire rope lubricant as claimedin claim 1 wherein the wax or polymer component comprises 2-15 wt % ofthe lubricant.
 8. The wire rope lubricant as claimed claim 1 wherein thewax or polymer has a melting point in the range 70-100° C.
 9. The wirerope lubricant as claimed in claim 1 wherein the base fluid isbiodegradable oil.
 10. The wire rope lubricant as claimed in claim 9wherein the base fluid has a viscosity in the range 450-2000 cSt at 40°C.
 11. The wire rope lubricant as claimed in claim 10 wherein the basefluid has a viscosity in the range 800-900 cSt at 40° C.
 12. The wirerope lubricant as claimed in claim 1 wherein the lubricant includes oneor more additives of: anticorrosive, anti-oxidant or anti-wearadditives.
 13. The wire rope lubricant as claimed in claim 1 having theformula: base fluid 88-91 wt %; carnauba wax 8-10 wt %; and additivesq.s.
 14. The wire rope lubricant as claimed in claim 1 wherein thelubricant is an offshore lubricant.
 15. A method of forming a wire ropehaving a plurality of wire strands comprising: the step of applying thewire rope lubricant of claim 1 between the wire strands.
 16. A wire ropehaving a plurality of wire strands and including the wire rope lubricantof claim
 1. 17. (canceled)